[PATCH v3 1/4] media: v4l: dev-decoder: Add source change V4L2_EVENT_SRC_CH_COLORSPACE

[ming.qian@oss.nxp.com]

From: Ming Qian <ming.qian@oss.nxp.com>

Add a new source change V4L2_EVENT_SRC_CH_COLORSPACE that
indicates colorspace change in the stream.
The change V4L2_EVENT_SRC_CH_RESOLUTION will always affect
the allocation, but V4L2_EVENT_SRC_CH_COLORSPACE won't.

Signed-off-by: Ming Qian <ming.qian@oss.nxp.com>
---
v3
- Improve the description according to comments

 .../userspace-api/media/v4l/vidioc-dqevent.rst       | 12 ++++++++++++
 .../userspace-api/media/videodev2.h.rst.exceptions   |  1 +
 include/uapi/linux/videodev2.h                       |  1 +
 3 files changed, 14 insertions(+)

diff --git a/Documentation/userspace-api/media/v4l/vidioc-dqevent.rst b/Documentation/userspace-api/media/v4l/vidioc-dqevent.rst
index 8db103760930..f317af57a92c 100644
--- a/Documentation/userspace-api/media/v4l/vidioc-dqevent.rst
+++ b/Documentation/userspace-api/media/v4l/vidioc-dqevent.rst
@@ -369,6 +369,18 @@ call.
 	loss of signal and so restarting streaming I/O is required in order for
 	the hardware to synchronize to the video signal.
 
+    * - ``V4L2_EVENT_SRC_CH_COLORSPACE``
+      - 0x0002
+      - This event gets triggered when a colorspace change is detected at
+	an input. This can come from a video decoder or a video receiver.
+	Applications will query the new colorspace information
+	(if any, the signal may also have been lost). If the signal is lost,
+	then that is a CH_RESOLUTION change, not CH_COLORSPACE.
+
+	For stateful decoders follow the guidelines in :ref:`decoder`.
+	If CH_COLORSPACE is set, but not CH_RESOLUTION, then only the
+	colorspace changed and there is no need to reallocate buffers.
+
 Return Value
 ============
 
diff --git a/Documentation/userspace-api/media/videodev2.h.rst.exceptions b/Documentation/userspace-api/media/videodev2.h.rst.exceptions
index 35d3456cc812..ac47c6d9448b 100644
--- a/Documentation/userspace-api/media/videodev2.h.rst.exceptions
+++ b/Documentation/userspace-api/media/videodev2.h.rst.exceptions
@@ -526,6 +526,7 @@ replace define V4L2_EVENT_CTRL_CH_RANGE ctrl-changes-flags
 replace define V4L2_EVENT_CTRL_CH_DIMENSIONS ctrl-changes-flags
 
 replace define V4L2_EVENT_SRC_CH_RESOLUTION src-changes-flags
+replace define V4L2_EVENT_SRC_CH_COLORSPACE src-changes-flags
 
 replace define V4L2_EVENT_MD_FL_HAVE_FRAME_SEQ :c:type:`v4l2_event_motion_det`
 
diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
index c8cb2796130f..242242c8e57b 100644
--- a/include/uapi/linux/videodev2.h
+++ b/include/uapi/linux/videodev2.h
@@ -2559,6 +2559,7 @@ struct v4l2_event_frame_sync {
 };
 
 #define V4L2_EVENT_SRC_CH_RESOLUTION		(1 << 0)
+#define V4L2_EVENT_SRC_CH_COLORSPACE		(1 << 1)
 
 struct v4l2_event_src_change {
 	__u32 changes;
-- 
2.43.0-rc1